Published German Patent Application No. DE-OS 27 42 084 (which corresponds to Cherin et al issued U.S. Pat. No. 4,142,776) discloses a connector for linear arrays of optical fiber waveguides including two axially connectable support members by which the end faces of the optical waveguides to be interconnected are coupled together, each of the support member being provided with a number of parallel grooves in which the ends of the optical waveguides are respectively seated and a guide member into which the two support members are inserted and in which they are guided along two sidewalls of a prism-shaped chamber.
In a prior-art connector of this kind, the two support members for the optical waveguides and the guide member receiving the latter have an approximately prismatic cross section. Two base surfaces of the guide member, which meet at an included angle alpha, and the two corresponding surfaces of each of the two support members must all be accurately machined to ensure the required precise axial alignment of the individual optical fibers. Between the top cover of the two support members and the upper surface of the guide member, there may be a certain amount of play; in that case, the reference surfaces of the support members and of the guide member are held in contact with one another by means of screws.
It is to be noted that in such a prior art connector design, it is very difficult to consistently machine both pairs of reference surfaces so precisely that the required precise axial alignment of all the optical waveguides to be connected can be achieved. If measurements on the already assembled and mated multiway connector show that the insertion loss is unacceptably high, it is difficult to remachine the entire reference surfaces and in any event such remachining will impair the desired tight fit of the support members in the guide member.
It is also to be noted that in the prior-art connector the force by which the end faces of the two support members are urged against each other depends on various random factors present during mating, including the frictional force between the support members and the guide member. No source of a precisely defined contact pressure is provided to ensure that the ends of the two optical waveguides abut without leaving any air gap between them.